I was wondering: what number of seeds to germinate for each temperature range would be significant for my data?

Even though I have 35+ sources; none of them state the amount of seeds which they germinated (total or for each temperature range), rather, they simply conducted calculations with the mysterious total percentage of the seeds which germinated, which leads me to think that the total amount of seeds needed aren't significant and rather it's how many of those germinated, but then again, conducting a germination test with 2 seeds doesn't sound so good in practical terms. So what do you think? What number of seeds would be safe to use? My supervisor suggested I used 50. How overkill is that?